Hello. After saving a code <p class="numblocks num-3"><span>1</span>text of element</p> span is missing and I see this at admin panel: <p class="numblocks num-3">1text of element</p> and this at the site: 1text of element
Did you just try to disable this WYSIWYG editor totally for test? It is impossible to help you without seeing this page HTML source and detect whether tags are stripped or not. If they are stripped it is for 100% your editor issue.